OK. Before I start I would like to say that I'm not very good with V Gen Pokemon. But, hey one can try right?
Anyway, on with the suggestions:
Tyranitar @ Choice Band
Nature: Adamant
Ability: Sand Stream
EV Spread: 180hp / 252atk / 76spe
Moves:
Stone Edge
Crunch
Earthquake / Pursuit / Fire Punch
Aqua Tail
Stone Edge is key to this set. After Choice Band boost Stone Edge can easily OHKO many Pokemon in the metagame even when hitting neutral damage. It can even 2HKO walls such as Skarmory and Forretress which makes it effective against stall teams.
Crunch serves as an accurate secondary STAB move and provides neutral coverage on Pokemon that resist Stone Edge (Swampert, Bronzong and Metagross). In this day and age Earthquake is pretty much staple as it provides good coverage (5 Pokemon types).
The final slot provides Tyranitar with much needed type coverage: Aqua Tail hits Hippowdon, Gliscor and even opposing Tyranitar. It also provides further neutral coverage and is overall a reliable attack. If you feel Earthquake is too dangerous to be locked into you can opt for Pursuit or even Fire Punch. Pursuit would be my personal choice as you can catch Pokemon on a switch and deal decent damage thanks to STAB. Fire Punch allows Tyranitar to OHKO Scizor and Forretress and potentially 2HKOing Skarmory and Bronzong.
Garchomp @ Life Orb / Haban Berry
Nature: Jolly
Ability: Sand Veil
EV Spread: 4hp / 252atk / 252spe
Moves:
Swords Dance
Outrage / Dragon Claw
Earthquake
Stone Edge / Fire Fang
After a Swords Dance, and the power boost from Life Orb Garchomp is nearly unstoppable offensively. He is able to outspeed many of the other Pokemon in the metagame and is capable of OHKOing even the most physically defensive Pokemon. This, added to STAB Earthquake completely wreck any grounded steel types.
Outrage is preferred simply because the main goal is to deal damage and sweep as quickly as possible. What better way to do that than with a move as powerful as Outrage?
If you feel Outrage is too dangerous Dragon Claw is a viable replacement and still provides STAB. With a base power of 80 it can still hit foes that don't resist pretty hard. Stone Edge is preferred over Fire Fang as it can deal with Skarmory. Fire Fang is still an option however, if you feel Stone Edge is too inaccurate (don't use any special fire type attack as you would be wasting those valuable attack EVs.
Ferrothorn @ Leftovers
Nature: Sassy
Ability: Iron Barbs
EV Spread: 252hp / 4atk / 252spdef
Moves:
Spikes
Power Whip / Gyro Ball
Gyro Ball / Leech Seed
Stealth Rock / Protect / Thunder Wave
Meh... What to say... Ferrothorn can switch in to many sweepers and users of choice items and set up entry hazards while the opponent does little damage or switches. It can keep repeating this process, which as a result can aid stall teams. If you opt for Power Whip in slot two then I recommend Gyro Ball for slot three as it provides STAB. If you opt for Gyro Ball in slot two then I recommend Leech Seed in slot three.
Slot four is really personal preference. Experiment with each option and decide which one you like best... Thats all I got for this Pokemon. xD.
Skarmory is fine. (edit: i'd recommend shed shell on skarmory, otherwise it's magnezone bait)
I may do the rest later. Also if you could update your post so I know who you are currently using?
I hope this helps.
EDIT: Oh, yeah. If you get the time, could you rate my team? xD